1. Field of the Invention
The present invention relates to a radio transceiver, and more particularly, to a radio transceiver having a plurality of switchable antennas.
2. Description of the Prior Art
Dipole antenna is commonly used in various radio transceivers such as mobile phones (GSM, DCS, DECT, etc.) for transmitting and receiving radio signals. Such dipole antenna can receive radio signals from all directions and thus is widely used in radio transceivers. The disadvantage of such dipole antenna is its low efficiency. In most circumstances, the radio signals are strong in certain directions and weak in others. But the dipole antenna can not enhance its efficiency according to this situation. In the meanwhile, a patch antenna is very direction-oriented. Only radio signals from the direction facing the patch antenna can be efficiently received. However, patch antennas are seldom used in radio transceivers, especially mobile phones. Because radio transceivers must be able to receive radio signals from all directions.